Reflection xterm - need some tuning assistance

Hi,
new job where they use Reflection on windows desktop that I haven't used before. Two things I need to change or adjust and cannot seem to find. First, I use Windows Alt-tab extensively to switch between windows including reflection xterm window. When I switch to one of those, a tab character prints onto the screen every time I switch to that window. I'd like for that not to happen. That phenomena hasn't happened in the past using vnc, Exceed, putty, etc. Second, I'd like to know how to change the default window size. Product Details:
I launch xterm session from Reflection X Manager using a clone of X client - "Linux - xterm". Help/About says :

 Reflection X Advantage Version 5.1 (5.1.622). 

Command line is:

 (xterm -sl 2000 -fn 10x20 -sb -ls -display %IP#% -name %T% &), host type=Linux, Secure Shell.

thx for assistance

I think I found part of the answer just now. I edited a copy of the keyboard's Explicitly Mapped keys for TAB character to be "NoSymbol, ,Tab" instead of "Tab, Tab" and that seems to have solved the tab issue after I bounced the X Manager. I had tried the same earlier and it didn't work, although I didn't bounce the Manager then. I'm wondering why I don't get a tab at all now though. I can live with space bar, but I would like TAB key to actually make a tab space.

---------- Post updated at 10:16 AM ---------- Previous update was at 08:49 AM ----------

(xterm -geometry 148x32 -sl 2000 -fn 10x20 -sb -ls -display %IP#% -name %T% &)
added the -geometry 148x32 and that got my column width fixed,
however the terminal window starts too far to the right. Now I'm trying to find out how to get the terminal window to start on the far left of the screen, if anyone knows that.
thx

---------- Post updated at 10:35 AM ---------- Previous update was at 10:16 AM ----------

ended up with this:

 (xterm -geometry 160x32+0+100 -sl 2000 -fn 10x20 -sb -ls -display %IP#% -name %T% &)

just needed to use the whole -geometry command. +0 being far left margin of the screen and +100 being 100 something down from the top of the screen (pixels maybe?).

Ok, so remaining problem is how to get my tab key to do a tab, but also have the alt-tab issue remain fixed.