OK, If you only need to buy the scope mount then go ahead and give it a try
A few things to note
The adaptor contains a small magnet and when the adaptor is fitted to the Thunder body, it causes a different version of the software to run
These differences include:
a. The menu now appears in the middle of the display rather than at the left side of the display
b. The "live" area of the display becomes smaller (hence reducing resolution)
c. Some functions are disabled including digital zoom
d. A display calibration function becomes available. This function is accessed by pressing the up and down buttons together and allows the display to be shifted so that the point of impact with and without the add-on can be made the same
When the scope mount is attached to the adaptor and the whole add-on fitted to the scope (using rubber insert that best fills the gap between the outside of the scope and the inside of the scope mount) I suggest you try the following:
(I am assuming your glass scope is already zeroed)
a. Bring up the main menu and go into reticle. Bring up reticle 1 and, with x=0 and y=0, adjust the position of the the add-on such that your scope reticle and the Thunder reticle are as closely aligned as you can get them and then lock the add-on in position and then switch the reticle off
b. Fire a shot at a target at your normal zero range and note the point of impact
c. If the point of impact with the add-on fitted is close enough to the POI without the add-on that you don't feel the need for any adjustment - then it's your lucky day!
d. Assuming that adjustment is needed then it's the add-on display that must be adjusted - do not touch your scope dials
e, Press the up and down buttons together to bring up the display calibration screen. This should show x=0 and y=0. IIRC increasing x moves the display to the right and increasing y moves the display. Basically, adjust the x and y values until the scope reticle is aligned with the point of impact.
f. Fire another shot to check if the adjustment is correct. if not, continue making adjustments to the x and y values until the point of impact is where you are aiming
g. OK, so now we have the add-on zeroed to your scope, but we need to make sure that when the add-on is removed and then re-fitted, that zero is maintained
h. There are 2 ways to do this.
The first is to leave the scope mount on the scope and remove the Thunder body and adaptor from the mount. This pretty much guarantees that you won't lose zero but the scope mount does reduce the amount of light getting into the scope plus there is potential for the scope mount to get damaged.
The second and I think better method is as follows:
1. After successfully zeroing the add-on to the scope, switch on reticle 1 (or any reticle you prefer) and adjust it's x and y values so that it is perfectly aligned with your glass scope reticle
2. Remove the complete add-on from the scope (body, adaptor and mount) and then refit it to the scope
3. Manually adjust the position of the add-on such that the add-on reticle and your glass scope reticle are as closely aligned as you can manage and lock the add-on in position
4. Fire another shot at the target to confirm that the add-on is still zeroed
Hope that helps
Cheers
Bruce