Simple main effects - alpha correction

#1
Hi, I am hoping someone may be able to help me with this as I have found a lot of contradictory information online.

I have a between-subjects 2(group: low vs. high) x 5(condition: c1, c2, c3, c4, c5) design. When running the ANOVA I find a significant group*condition interaction, so I therefore want to decompose this analysis by using a simple effects approach to locate the root of the significant interaction term (i.e. I want to look at the effect of condition at each level of group).

I have two questions:
1) What method of multiple comparison control should I use? Nearly every example I see online uses no adjustment at all, which definitely is a red flag for me. However, a Bonferroni correction in this case may be far too conservative... Unfortunately SPSS only offers the choice of LSD, Bonferroni, or Sidak...
2) When computing a correction should I treat the pairwise comparisons at each level of group as independent. To put it more clearly: If I chose a bonferroni correction, should I apply the correction within each set of group comparisons (.05/10) or at the global level of total comparisons (.05/20)? Obviously these two approaches provide different results.

If anyone can provide any suggestions I would greatly appreciate it.

Thanks in advance