Since Pix is on leave let me try to answer your question.
1. NumberOfSlotsSpreadTrans(TX Integer).
This parameter is used to control the delay of RACH retransmission after a RACH Collision ( or any case when MS does not receive AGCH in response to a RACH it assumes its a collision ans retries after a randon interval controlled by TX_Integer. The need for random interval is so that if its a RACH Collision the other MS from whose RACH this collided would also be retrying so the interval should not be same else it would be an endless loop so both retry after random intervals. Now the reason you have different values for GSM and DCS does not seem to be useful (both have equal probability of collision). IT can be same only time when its done intentionally is when you expect system to respond slowly in some cases then its kept at its maximum value (one case is having ABIS on VSAT).
2. for the RMS Template well RNO and NPA have different templates (I think more than 8 which themselves can be altered )for displaying values of level / quality / TA bins; each template for example has information on how to distribute TA samples of 0-64 between bin 0 to 7.
for example on Template could be [0-1],[1-2],[2-3],[3-4],[4-5],[5-6],[6- above]
another template could be
[0-5],[6-10],[11-15],[16-20],[20-30],[30-45],[45 above] and so on and based on the cell’s coverage area you can select the RMS Template that suits, one method may be like you can have one template for Rural and another for Urban and set to cells based on their morphology.
Hope this helps you, rest Pix can add on.