You do know that all FOs are paid the same regardless of equipment? Also, realize that in order to get the first available upgrade, if you hire on as a 170 FO, you will probably have to cross over to CHQ and upgrade into the 145 or CRJ. 145 and CRJ CAs can bid to the 170, so its quickly becoming senior equipment.

Unless you have a QOL reason for desiring a certain base, take the first class they offer you.